1. Field of the Invention
This invention relates to powdered abrasive cleansers comprising synthetic surfactants, abrasives and encapsulated perfume.
2. Background Art
Powdered abrasive cleansers have long been known to be useful for scouring porcelain sinks and fixtures, hard metallic materials, pots and pans, and similar surfaces which require high levels of mechanical abrasive for cleaning. The formulation of such powdered abrasive cleansers is discussed in great detail in U.S. Pat. Nos. 3,583,922, McClain et al., issued June 8, 1971; 3,829,385, Abbott, Jr., et al., issued Aug. 13, 1974; 3,715,314, Morganstern, issued Feb. 6, 1973; and U.S. Pat. No. 4,287,080, Siklosi, issued Sept. 1, 1981, all of said patents being incorporated herein by reference.
Microencapsulation of various hydrophobic liquids is well known. Microcapsules have been suggested for encapsulation of perfumes, medicines, adhesives, dyestuffs, inks, etc. It has specifically been suggested to microencapsulate fragrances for use in liquid or solid fabric softeners. See, e.g., U.S. Pat. No. 4,446,032, Munteanu et al., issued May 1, 1984, incorporated herein by reference. The individual perfume and/or flavor compounds which can be encapsulated are also well known, having been disclosed in, e.g., U.S. Pat. No. 3,971,852, Brenner et al., issued July 27, 1976; U.S. Pat. No. 4,515,705, Moeddel, issued May 7, 1985; U.S. Pat. No. 4,741,856, Taylor et al., issued May 3,1988, etc., all of the above patents being incorporated herein by reference.
Microencapsulation techniques, including so-called "coacervation" techniques, are also well known, having been described, for example, in U.S. Pat. No. 2,800,458, Green, issued July 23, 957; U.S. Pat. No. 3,159,585, Evans et al., issued Dec 1, 1964; U.S. Pat. No. 3,533,958, Yurkowitz, issued Oct. 13, 1970; U.S. Pat. No. 3,697,437, Fogle et al., issued Oct. 10, 1972; U.S. Pat. No. 3,888,689, Maekawa et al., issued June 10, 1975; Brit. Pat. 1,483,542, published Aug. 24, 1977; U.S. Pat. No. 3,996,156, Matsukawa et al., issued Dec. 7, 1976; U.S. Pat. No. 3,965,033, Matsukawa et al., issued June 22, 1976; and U.S. Pat. No. 4,010,038, Iwasaki et al., issued Mar. 1. 1977, etc., all of said patents being incorporated herein by reference.
Other techniques and materials for forming microcapsules are disclosed in U.S. Pat. No. 4,016,098, Saeki et al., issued Apr. 5, 1977; U.S. Pat. No. 4,269,729, Maruyama et al., issued May 26, 1981; U.S. Pat. No. 4,303,548, Shimazaki et al., issued Dec. 1, 1981; U.S. Pat. No. 4,460,722, Igarashi et al., issued July 17, 1984; and U.S. Pat. No. 4,610,927, Igarashi et al., issued Sept. 9, 1986, all of said patents being incorporated herein by reference.
For certain utilities such as that disclosed in U.S. Pat. No. 4,446,032, supra, it is desirable to have a strong capsule wall to permit preparation of finished compositions that contain microcapsules utilizing processes that tend to destroy capsule walls and yet have the capsules readily activated in some way during use. Heretofore, it has been thought that the capsule walls should be water-soluble, as disclosed in British Pat. No. 1,367,622, Bradbury et al., incorporated herein by reference. The '622 British patent teaches that there is an essential balance between strength and water solubility required and that the degree of cross-linking should be low. 1% and 1.5% of glutaraldehyde cross-linking agent were preferred over 2%. Water-insoluble capsules are implicitly considered to be ineffective.